Sperm Competition - Offensive Adaptations

Offensive Adaptations

Offensive adaptation behavior differs from defensive behavior because it involves an attempt to ruin the chances of another male's opportunity in succeeding in copulation by engaging in an act that tries to terminate the fertilization success of the previous male. A male on the offensive side of mate-guarding may terminate the guarding male's chances at a successful insemination by brawling with the guarding male to gain access to the female. In Drosophila, males release seminal fluids that contain additional toxins like pheromones and modified enzymes that are secreted by their accessory glands intended to destroy the sperm that have already made their way into the female's reproductive tract from a recent copulation. Based on the "last male precedence" idea, some males can remove sperm from previous males by ejaculating new sperm into the female; hindering successful insemination opportunities of the previous male.